Machine Availability, also know as uptime, is typically one of the elements in the Service Level Agreement and means the percentage of time a machine is in operation.

Why Does it Matter to Field Service

Uptime is a key component of many SLA's.  Miss the uptime, and it will cost the company money.  Often, Organizations will guarantee that a customer will have use of the equipment for a minimum percentage of time (ex: 97% of the time they will have full use of machine).  Or they may make guarantees of machine availability during specific hours; such as commuter trains operating between 4am and 12am, with a short 4 hour window for maintenance.